So instead of hijacking ske714's thread, I thought I'd start another. I have a handful of MkII's and I'm thinking of having some threaded for eventual suppressor use. Given the fact that I'll be using Blazers and run of the mill bulk packs, what is the optimal barrel length that would keep most loads subsonic? Have them cut to 4.5" or 5"? No, I don't want to buy PacLIte uppers (just more of a PITA in MD) and the host guns are bull barreled 5.5"